Suspend AstraZeneca use for people under 55, vaccine committee recommends
Canada's National Advisory Committee on Immunization (NACI) is recommending provinces pause the use of the AstraZeneca-Oxford COVID-19 vaccine on those under the age of 55 because of safety concerns — guidance most provinces said today that they would follow.
The change comes following reports out of Europe of very rare instances of blood clots in some immunized patients — notably among younger women.
But 300,000 of these shots have been administered in Canada already, with no reports of blood clots here, officials said. The blood clotting problem also has not been reported in people who have received mRNA vaccines like the Pfizer and Moderna products.
Speaking to reporters Monday, Dr. Shelley Deeks, the vice-chair of NACI, said that with "substantial uncertainty" around cases of vaccine-induced thrombocytopenia (VIPIT) in people with low platelets, the committee is recommending the suspension of shots in all people under 55 as a "precautionary measure."
Based on early research out of Europe, VIPIT seems to be rare, occurring in anywhere from 1 in every 125,000 to 1 in 1 million people.
The European Union's drug watchdog, the European Medicines Agency, has said it could not definitively rule out a link between the vaccine and rare types of blood clots associated with thrombocytopenia.
Specifically, it pointed to 18 cases of an extremely rare type of blood clot called cerebral venous sinus thrombosis (CVST), a condition that is much more common in women than men. Most of the cases occurred within 14 days of receiving the AstraZeneca shot, and the majority were in women under the age of 55.
Dr. Howard Njoo, Canada's deputy chief public health officer, said people who develop stroke-like medical symptoms after receiving the AstraZeneca vaccine — shortness of breath, chest pain, leg swelling, abdominal pain, sudden onset of headaches or blurred vision — should immediately seek medical attention. There is no risk for people who have not developed such symptoms 20 days post-vaccination.
Asked why the shot is still recommended for people over the age of 55 given the many unknowns, Dr. Caroline Quach-Thanh, the chair of NACI, said the early data indicate that the rare blood clots are most common in younger people.
She said older Canadians should take whatever vaccine they can get because contracting COVID-19 poses a much greater health risk to them than the outside chance of developing this sort of blood clot.
"If you look at this overall, it's a vaccine that prevents complications and deaths. We're trying to contrast the risks and benefits," she said.